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Insights into the in-situ degradation and fragmentation of macroplastics in a low-order riverine system

delete2025-05-02
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PRE
AI
A
Austin Gray *
S
Sequeira, Luisana Rodriguez
T
Tessa Thibodeau
M
Montgomery, Allison
S
Sam Purvis
K
Kathryn Ouimet
T
Tina Dura
K
Kathleen Mayer
DOI:10.1093/etojnl/vgaf116delete
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Abstract

Abstract

En 中文
Inland riverine systems are major conduits of microplastics (MPs) to coastal environments. Plastic materials that pass through riverine systems are subjected to various degradation processes that facilitate their fragmentation into MPs. Low-order streams, a critical yet understudied part of river networks, significantly influence the fate and transport of MPs. Here, we investigate the in situ degradation of common macroplastic polymers (e.g., low-density polyethylene, polyethylene terephthalate, and polystyrene) and their fragmentation into MPs in urban and forested streams. We deployed macroplastic items and a natural biodegradable polymer (cellulose) into a stream habitat for 52 weeks. We found that regardless of stream type (forested or urban), macroplastic polymers produced MPs in 2 weeks, with polystyrene having the highest fragmentation rate (8 particles/week). We explored several degradation indices (carboxyl index, hydroxyl index, and vinyl index), which revealed that photooxidation played a role in macroplastic degradation over time. Another driver of degradation was biofilm formation observed on the surface of all items, mainly composed of diatoms. Finally, we found that field-aged macroplastics can leach plastic-derived dissolved organic. Our study narrows the knowledge gap regarding MP degradation and fragmentation in freshwater by providing real-time in situ data on the rate of polymer fragmentation in a low-order riverine system.
Keywords:
plastic degradation
biofilm
oxidation
fragmentation
freshwater

Journal

Environmental Toxicology and Chemistry cover
Environmental Toxicology and Chemistry
IF:
2.8
Papers:
9.7K
Citations:
1.9W

Organization

V
Virginia Polytechnic Institute and State University
Scholars:
757
Papers: 387
Citations: 46
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